Networking of devices is a ubiquitous trend in business (commercial, industrial, institutional) and also consumer markets. Examples where networked devices are used include building automation systems, e.g. for lighting, heating/ventilation/cooling, and safety, where various devices like light ballasts, switches, daylight/occupancy sensors, actuators, meters etc., are inter-connected such as wirelessly via RF modules, for example. The large number of devices in a control network, together with their small footprint and potentially very complicated application logic to be run on them, require new approaches to control network management.
To reduce complexity of creating or configuring networks and node addressing, various systems and methods are known for network addressing, where addresses of nodes in a network are assigned and dynamically reassigned, such as based on the position and/or number of nodes in a tree or sub-tree of the node. For example, U.S. Patent Application Publication No. 2006/0023643 to Lim, which is incorporated herein by reference in its entirety, describes a method of adaptively reassigning address of nodes according to changes in volume in a wireless network, where the network address of the node is calculated from the position of that node in the routing tree.
Another network system management method is disclosed in International Publication Number WO 2006/091042 to Jeon et al. (Jeon), which is incorporated herein by reference in its entirety. This method makes sure that only one unique device in the network fulfills a certain role. For instance, if two refrigerators connect to the network, the Jeon method ensures that only one device will fulfill the role of refrigerator in the network, such that it will be uniquely known which device is the refrigerator. That is, the first refrigerator that is connected to the network will be given that address; further connected refrigerators are either ignored or replace the currently connected refrigerator. In the Jeon system, only the role of a device is taken into account; the location and other user-relevant information are not taken into account, where for example, two refrigerators cannot be properly addressed and connected to the Jeon network. Other network management systems group related nodes and assign them a unique group address, or automatically assign network addresses to devices upon joining the network, where such device network addresses are also referred to as physical device addresses.
However, use of physical device addresses as is currently done in conventional network systems, such as control systems (e.g. using the ZigBee™ protocol), complicates the design and maintenance of the systems. For example, if control logic is defined using physical device addresses, then the network design, e.g. with respect to setup and maintenance procedures, becomes inflexible and more error-prone, particularly when the network is defined or setup by non-technical people.
One problem with conventional control systems is that all the physical device addresses must be known at or during the time when the control logic is being designed. This means that the logic designer needs to program directly on the physical installation of the network. Hence, the logic designer needs first to find out exactly the location in the network of physical nodes and associated physical addresses. In practice, this means that for each and every network instance, dedicated/additional logic design or programming needs to take place.
Another problem is that when a device is added once the network is up, a new or previously unknown physical address will have to be manually incorporated into the control logic. Thus, the logic designer again needs to partially reprogram the logic with a new physical address, for example.
A further problem is that of hot replacement of device in a system which often requires application and support logic re-installation on all devices hosting logic related to and/or wishing to communicate results to the replaced device. This is typically due to the use of physical device addresses (e.g., network addresses and/or hardware (HW) addresses of devices) for the logic design and application-related communication.
In addition, typically, the addresses assigned to devices or groups of devices are purely numerical, and are meaningless to users, and may even be unreadable by the user. For example, the assigned addresses in conventional systems and methods are machine addressing related to the device's position in the network tree as in ZigBee™. In TCP/IP networks, the machine addressing is related to the device's position in particular sub-network (e.g., if DHCP protocol is used, such as RFC2132 of IETF, as described in http://www.ietf.org/), or completely random (if IPv4 Link-Local addresses protocol is used, such as RFC3927 of IEFT as described in http://www.ietf.org/). Such user-unreadable or meaningless addressing often does not have anything to do with the device type and/or the actual device location in the environment. Rather, any location information used in conventional networks and addressing is related to the device node location in the network tree, and is not related to the actual device location in the environment.
Accordingly, there is a need for assigning logical addresses that include user-friendly identifiers.